Yield, components of yield and quality responses of groundnut cultivars (Arachis hypogaea L.) as influenced by photoperiod and a growth regulator

In a field experiment conducted during the winter/spring (post-rainy irrigated season) of 1982/83 at ICRISAT (Hyderabad, India) six cultivars of groundnuts representing the two subspecies of Arachis hypogaea L. were investigated for their responses to photoperiod and a growth regulator, Kylar (succinic acid 2,2-dimethylhydrazide = SADH). The short-day treatment was the normal winter/spring day at Hyderabad (latitude 17° N). Long-day conditions were achieved by extending the days to 22.00 h. Kylar was applied at the rate of 1 kg/ha a.i. at early pod-set. Cultivar variability for photoperiod responses was found in both subspecies for pod yield. While four cultivars achieved greater pod yields (38–106%) under short-day conditions, TMV-2 and Robut 33-1 had slightly increased yield in long days. Kylar decreased the differences in yield created by the two daylengths. Change in the proportion of large (View the MathML source) seeds was the main factor responsible for the yield differences resulting from the photoperiodic treatments. The Kylar-treated plants produced more large kernels. Generally, the shelling percentages were increased by the Kylar short-day treatments. Only TMV-2 had a significantly increased shelling percentage under long-day conditions. At final harvest all cultivars, except for TMV-2, had accumulated higher levels of vegetative dry matter in the long-day treatment. Kylar, again excepting TMV-2, increased vegetative weights/m2 at final harvests in both photoperiods